scholarly journals Investigation of Permanent Deformation Behavior of Steel Slag Asphalt Mixture under Indoor Simulation

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Minghua Wei ◽  
Chao Yang ◽  
Jun Xie ◽  
Shan Liu ◽  
Fusong Wang ◽  
...  

Previous studies have indicated that steel slag can be used as a substitute for natural aggregates in asphalt mixture, while little attention has been paid to systematic investigation of the influences of various external environmental factors on deformation resistance of steel slag asphalt mixture. In order to understand the service behavior of steel slag asphalt mixture, its permanent deformation under different condition was investigated based on an indoor simulation test. The chemical composition, microscopic structure, surface texture, and volume stability of steel slag were firstly characterized. The uniaxial repeated loading test and standard wheel-tracking test were applied to evaluate the effect of temperature, stress levels, and water damage on the permanent deformation of AC-16 and AC-20 steel slag asphalt mixtures. The results indicate that a higher content of alkaline oxide and high-grade texture index existing in steel slag contribute to its strong absorptivity and adhesion of asphalt. The steel slag demonstrates fine volume stability due to its lower free-CaO (f-CaO) content, autoclave chalked ratio, and immersion expansion ratio. The permanent deformation of steel slag asphalt mixtures increases rapidly under higher stress and temperatures in contrast to lower increment at lower stress and temperatures. Asphalt mixtures at higher stress and higher temperatures and water condition exhibit larger rutting deformation and inferior rutting resistance. AC-16 steel slag asphalt mixture has superior resistance to permanent deformation than AC-20 asphalt mixture. Rutting factors show different degrees of impact in a decreasing order of temperature, water damage, and stress levels. The findings have significant implications for providing a theoretical basis for reusing steel slag in pavement construction and facilitating engineering application of steel slag asphalt mixture.

2020 ◽  
Vol 6 ◽  
pp. 42-60
Author(s):  
Abdalrhman Abrahim Milad ◽  
Ahmed Suliman B. Ali ◽  
Nur Izzi Md Yusoff

The possibility of using waste materials in road construction is of great interest as their utilisation may contribute to reducing the problems of hazard and pollution and conserve natural resources. Thus, there is an urgent need to find a sustainable method for using waste materials as a substitute in the standard asphalt binders. There are several concerns about the physical and chemical properties and mechanical performance of asphalt pavements incorporated with waste material in the effort to reduce permanent deformation of the road surface. This review article presents a brief discussion of the asphalt mixtures modified with waste material, and the recycled materials used as a modifier in the asphalt mixture. The present paper summarises the use of crumb rubber, crushed concrete, steel slag, glass fibre and plastic waste in asphalt mixtures. The use of waste materials as a modifier in asphalt mixture resulted in improved asphalt pavement performance. Results advocate that rubberised asphalt mixture with desired properties can be designed as an additive with a friendly environmental approach in construction materials. The researches that adopted the influence of usage, recycle waste material to improve the performance of the asphalt of the road are still limited compared to other construction fields. Doi: 10.28991/cej-2020-SP(EMCE)-05 Full Text: PDF


2021 ◽  
Vol 54 (5) ◽  
Author(s):  
M. Bueno ◽  
R. Haag ◽  
N. Heeb ◽  
P. Mikhailenko ◽  
L. Boesiger ◽  
...  

AbstractIncorporating crumb rubber (CR) using the dry process, directly in the asphalt mixture rather than into the bituminous binder requires no plant retrofitting, and therefore is the most practical industrial method for CR incorporation into asphalt mixtures. Nevertheless, very few large scale studies have been conducted. This work uses a holistic approach and reports on the functional and environmental performance of asphalt mixtures with different concentrations of CR fabricated employing the dry process in asphalt plants. Gaseous emissions were monitored during the production and laboratory leaching tests simulating the release of pollutants during rain, was conducted to evaluate the toxicology of both the CR material alone and the modified asphalt mixtures. In addition, laboratory compacted samples were tested to assess their fatigue behavior. Furthermore, noise relevant surface properties of large roller compacted slabs were evaluated before and after being subjected to a load simulator (MMLS3) to evaluate their resistance to permanent deformation. The results confirm that comparable performance can be achieved with the incorporation of CR using the dry process for high performance surfaces such as semi-dense asphalt, which usually require the use of polymer modified binders. Environmental performance improvement can be achieved by a washing step of the CR material that could remove polar CR additives which have commonly been used as vulcanization accelerator during rubber production.


Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 663 ◽  
Author(s):  
Baowen Lou ◽  
Zhuangzhuang Liu ◽  
Aimin Sha ◽  
Meng Jia ◽  
Yupeng Li

Excessive usage of non-renewable natural resources and massive construction wastes put pressure on the environment. Steel slags, the main waste material from the metal industry, are normally added in asphalt concrete to replace traditional aggregate. In addition, as a typical microwave absorber, steel slag has the potential to transfer microwave energy into heat, thus increasing the limited self-healing ability of asphalt mixture. This paper aims to investigate the microwave absorption potentials of steel slag and the effect of its addition on road performance. The magnetic parameters obtained from a microwave vector network analyzer were used to estimate the potential use of steel slag as microwave absorber to heal cracks. Meanwhile, the initial self-healing temperature was further discussed according to the frequency sweeping results. The obvious porous structure of steel slag observed using scanning electron microscopy (SEM) had important impacts on the road performance of asphalt mixtures. Steel slag presented a worse effect on low-temperature crack resistance and water stability, while high-temperature stability can be remarkably enhanced when the substitution of steel slag was 60% by volume with the particle size of 4.75–9.5 mm. Overall, the sustainability of asphalt mixtures incorporating steel slag can be promoted due to its excellent mechanical and microwave absorption properties.


Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2084 ◽  
Author(s):  
Piotr Mackiewicz ◽  
Antoni Szydło

We present two methods used in the identification of viscoelastic parameters of asphalt mixtures used in pavements. The static creep test and the dynamic test, with a frequency of 10 Hz, were carried out based on the four-point bending beam (4BP). In the method identifying viscoelastic parameters for the Brugers’ model, we included the course of a creeping curve (for static creep) and fatigue hysteresis (for dynamic test). It was shown that these parameters depend significantly on the load time, method used, and temperature and asphalt content. A similar variation of parameters depending on temperature was found for the two tests, but different absolute values were obtained. Additionally, the share of viscous deformations in relation to total deformations is presented, on the basis of back calculations and finite element methods. We obtained a significant contribution of viscous deformations (about 93% for the static test and 25% for the dynamic test) for the temperature 25 °C. The received rheological parameters from both methods appeared to be sensitive to a change in asphalt content, which means that these methods can be used to design an optimal asphalt mixture composition—e.g., due to the permanent deformation of pavement. We also found that the parameters should be determined using the creep curve for the static analyses with persistent load, whereas in the case of the dynamic studies, the hysteresis is more appropriate. The 4BP static creep and dynamic tests are sufficient methods for determining the rheological parameters for materials designed for flexible pavements. In the 4BP dynamic test, we determined relationships between damping and viscosity coefficients, showing material variability depending on the test temperature.


Author(s):  
Gerald A. Huber ◽  
Xishun Zhang ◽  
Robin Fontaine

The Strategic Highway Research Program (SHRP) spent $50 million researching asphalt binders and asphalt mixtures and provided three main products: an asphalt binder specification, an asphalt mixture specification, and Superpave, an asphalt mixture design system that encompasses both the binder and mixture specification. SHRP researchers have provided tools that promise more robust asphalt mixtures with reduced risk of premature failure. Implementation of the specifications and mix design system will require overcoming several obstacles. Superpave must be demonstrated to be practical and easy to use. The impact of Superpave aggregate requirements on aggregate availability must be determined. The Superpave gyratory compaction procedure has been uniquely defined and then calibrated to traffic volume. The reasonableness of this approach must be tested in widespread application. Perhaps the largest implementation hurdle exists in the performance models. Expensive test equipment is necessary to do the performance-based tests. The performance predictions must be established as reasonable to justify the cost. A highway reconstruction project containing three Superpave Level 1 mix designs is documented including quality control done with the Superpave gyratory compactor. Superpave Level 2 performance-based tests were carried out to predict permanent deformation of the design and the mixture as constructed. The performance-based engineering properties obtained from the tests are evaluated, and the reasonableness of the performance prediction models is discussed.


Author(s):  
Jamilla Emi Sudo Lutif Teixeira ◽  
Aecio Guilherme Schumacher ◽  
Patrício Moreira Pires ◽  
Verônica Teixeira Franco Castelo Branco ◽  
Henrique Barbosa Martins

The influence of steel slag expansion level on the early stage performance of hot mix asphalt (HMA) is evaluated. Initially, samples of Linz-Donawitz type steel slag with different levels of expansion (6.71%, 3.16%, 1.33%) were submitted to physical, mechanical, and morphological characterization to assess the effects of expansion on individual material properties. Steel slag was then used as aggregate in HMA to verify the effects of its expansion characteristics on the volumetric and mechanical performance of the asphalt mixture. Four different asphalt mixtures were designed based on Marshall mix design, using asphalt cement (pen. grade 50/70), natural aggregate (granite), and steel slag (in three different levels of expansion). The mechanical characteristics of the asphalt mixture were evaluated based on results from Marshall stability, indirect tensile strength, and resilient modulus testing. A modified Pennsylvania testing method (PTM) was also performed on the studied asphalt mixtures to verify the potential of asphalt binder film to minimize the expansive reactions of steel slag. It was observed that the level of steel slag expansion changes some of the material’s individual properties, which can affect the volumetric parameters of the mix design. The use of steel slag as aggregate in HMA also improves the mechanical properties of non-aged asphalt mixtures. Moreover, the expansive characteristics of this material could be minimized when combined with other asphalt mixture components.


2021 ◽  
Vol 293 ◽  
pp. 02029
Author(s):  
Tang-Baoli ◽  
Ren-yongqiang ◽  
Chen-Xiangmei ◽  
Hou-Huifang ◽  
Liang-Jianping

In order to study the high temperature performance of LM-S modified asphalt mixture and SBS modified asphalt mixture, repeated loading creep test was used to study the influence of temperature and deviatoric stress on the axial permanent deformation of the two kinds of asphalt mixture. At the same time, Permanent deformation, ε@5000, flow number FN and creep rate were select to evaluation of high temperature performance from different directions. The results show that the ε@5000 and creep rate are failed in the condition of high temperature and large deviatoric stress, so it hast widely practicable. The flow number FN is also limited by the conditions, which leads to the distortion of the flow number at lower temperature and smaller deviatoric stress so it is not easy to direct used as the evaluation index. Axial permanent deformation can reflect the permanent deformation in different cycles which is an excellent index to evaluate the high temperature performance of the two kinds of asphalt mixture, it is recommended to use axial permanent deformation to compare the LM-S modified asphalt mixture and SBS modified asphalt mixture The experimental results show that the axial permanent deformation of the LM-S modified asphalt mixture is always less than that of SBS modified asphalt mixture,it indicating that the high temperature rutting resistance of the LM-S modified asphalt mixture is better than that of SBS modified asphalt mixture.


2022 ◽  
Vol 12 (1) ◽  
pp. 490
Author(s):  
Caroline Moura ◽  
Lucas Nascimento ◽  
Carlos Loureiro ◽  
Mafalda Rodrigues ◽  
Joel Oliveira ◽  
...  

Steel slag is a byproduct generated as waste during the steelmaking process and can be considered a cost-effective and environmentally acceptable alternative to replace natural aggregates. Using steel slag aggregates (SSA) to produce asphalt mixtures promotes sustainability and circular economy principles by using an industrial byproduct as a raw material. Thus, this work mainly aims to design more sustainable asphalt mixtures with high amounts of SSA that fit the circular economy expectations. This work developed two asphalt mixtures with SSA for surface (AC 14 surf) and binder/base (AC 20 bin/base) courses. Initially, the excellent wearing and polishing resistance of SSA and their good affinity with bitumen demonstrated the potential of this byproduct to be used in asphalt mixtures. Then, when analyzing the influence of using two different SSA incorporation rates (50% and a percentage close to 100%) in both asphalt mixtures, it was concluded that the use of SSA should be limited to 75% to avoid excessive air void contents and durability problems. The importance of considering the different particle densities of SSA and natural aggregates was highlighted during the mix design by defining a relationship between an effective and equivalent binder content. Finally, the mechanical performance of AC 14 and AC 20 with 75% SSA incorporation was compared to identical conventional mixtures produced with natural granite aggregates. The results obtained showed that the asphalt mixtures with 75% SSA have some workability problems due to the rough and porous surface of SSA. However, they present an excellent water sensitivity and permanent deformation resistance, surpassing the performance of the conventional asphalt mixtures.


Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3601 ◽  
Author(s):  
Deyu Zhang ◽  
Linhao Gu ◽  
Junqing Zhu

This paper investigated the effects of aggregate mesostructures on permanent deformation behavior of an asphalt mixture using the three-dimensional (3D) discrete element method (DEM). A 3D discrete element (DE) model of an asphalt mixture composed of coarse aggregates, asphalt mastic, and air voids was developed. Mesomechanical models representing the interactions among the components of asphalt mixture were assigned. Based on the mesomechanical modeling, the uniaxial static load creep tests were simulated using the prepared models, and effects of aggregate angularity, orientation, surface texture, and distribution on the permanent deformation behavior of the asphalt mixtures were analyzed. It was proven that good aggregate angularity had a positive effect on the permanent deformation performance of the asphalt mixtures, especially when approximate cubic aggregates were used. Aggregate packing was more stable when the aggregate orientations tended to be horizontal, which improved the permanent deformation performance of the asphalt mixture. The influence of orientations of 4.75 mm size aggregates on the permanent deformation behavior of the asphalt mixture was significant. Use of aggregates with good surface texture benefitted the permanent deformation performance of the asphalt mixture. Additionally, the non-uniform distribution of aggregates had a negative impact on the permanent deformation performance of the asphalt mixtures, especially when aggregates were distributed non-uniformly in the vertical direction.


2020 ◽  
Vol 1007 ◽  
pp. 99-104
Author(s):  
Juraidah Ahmad ◽  
Mohd Rosli Hainin ◽  
Ekarizan Shaffie ◽  
Khairil Azman Masri ◽  
Mohd Amin Shaffi

The Simple Performance Test (SPT) can be used to characterize the strength and load resistance of asphalt mixtures. The objectives of this study are to determine the effect of temperature on the phase angle and dynamic complex modulus of the asphalt mixtures tested at 30°C, 35°C, 40°C, 45°C and 50°C at 25Hz, 20Hz, 10Hz, 5Hz, 1Hz and 0.5Hz frequencies. The asphalt mixtures of NMAS 12.5mm are prepared using asphalt binder PEN 80/100 and PEN 60/70. The asphalt mixtures are designed using the Superpave system and compacted using the Superpave Gyratory Compactor (SGC). The dynamic modulus test results showed that at a higher temperature, the stiffness of the asphalt mixtures is affected. The dynamic modulus of the mixtures is highest at 30°C and gradually decrease at 35°C, 40°C, 45°C and 50°C respectively. The dynamic modulus values for asphalt mixtures with bitumen grade PEN 60/70 are also higher compared to the asphalt mixtures with bitumen grade PEN 80/100. Results also showed that the low phase angle values indicate low viscosity of the asphalt binder due to increase in temperature. The present study is meaningful in understanding the asphalt mixture behaviour at different temperature and loading frequencies.


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